Background: Recent military experience reported casualties who receive >10 units of packed red blood cells (PRBC) in 24 hours have 20% versus 65% mortality when the fresh-frozen plasma (FFP) to PRBC ratio was 1:1 versus 1:4, respectively. We hypothesize a similar improvement in mortality in civilian trauma patients that require massive transfusion and are treated with a FFP to PRBC ratio closer to 1:1.

Methods: Four-year retrospective study of all trauma patients who underwent emergency surgery in an urban Level I Trauma Center. Patients were divided into two groups; those that received <=10 units or >10 units of PRBC during and after initial surgical intervention. Only patients who received transfusion of both FFP and PRBC were included in the analysis. The primary research question was the impact of initial FFP:PRBC ratio on mortality. Other variables for analysis included patient age, gender, mechanism, and Injury Severity Scale score. Both univariate and multivariate analysis were used to assess the relationship between outcome and predictors.

Results: A total of 2,746 patients underwent surgical intervention of which 1,985 (72.2%) received no transfusion. Of those that received transfusion, 626 (22.8%) received <=10 units of PRBC and 135 (4.9%) >10 units of PRBC. Out of the 626 patients that received <=10 units of PRBC, 250 (39.9%) received FFP and 376 (60.1%) received no FFP. All the patients that received >10 units PRBC received FFP. In univariate analysis, a significant difference in mortality was found in patients who received >10 units of PRBC (26% vs. 87.5%) when FFP:PRBC ratio was 1:1 versus 1:4 (p = 0.0001). Multivariate analysis in the group of patients that received >10 units of PRBC showed a FFP:PRBC ratio of 1:4 was consistent with increased risk of mortality (relative risk, 18.88; 95% CI, 6.32-56.36; p = 0.001), when compared with a ratio of 1:1. Patients who received <=10 units of PRBC had a trend toward increased mortality (21.2% vs.11.8%) when the FFP:PRBC ratio was 1:4 versus 1:1 (p: 0.06).

Conclusion: An FFP to PRBC ratio close to 1:1 confers a survival advantage in patients requiring massive transfusion.